Improving Highest Security Lightweight block cipher (HISEC) Algorithm Using Key Dependent S-box

: Information security is considered as a very critical issue in the transmission of information. Therforelossing or threatening the information transmission will therefore be a great loss in the process of transmitting the information. Recently, Lightweight block cipher Algorithms have gained wide acceptance and it is used in restricted applications, such as electronic passport, smart card


Introduction
There are many important applications that need high security lightweight block cipher algorithm like credit card, electronic passport, etc.After the evolution of electronic and communication applications, RFID technology has been used in many aspects of life, such as access control, parking and management, identification and goods tracking etc. [1].In this type of new encryption algorithm, applications of RFID technology have limitations, such as poor computational power, and the small storage space of that traditional block encryption such as AES which is not suitable for this kind of very restrictive environment.Thus, in recent times, lightweight block cipher algorithms have encountered a lot of interest compared with traditional block ciphers, lightweight block cipher algorithms have three main characteristics:[2] [3].


Security: Increasing the length of the key will increase security and cost, and vice versa.


Performance: Increasing cycles will increase security and reduce performance and vice versa.


Cost: The representation of the Hardware algorithm depends on cost.
High security lightweight block cipher algorithm have gained more attention recently.A recent study was handled by Jahan et al (2017) [4].In this study, an investigation on the issue aiding write operations on the outsourced data for clients using mobile devices was presented.The Ciphertext-Policy Attribute-based Encryption (CP-ABE) scheme was considered because it is convenient in aiding access control in outsourced cloud environments.One of the flaws of CP-ABE is that users can adjust the access policy stated by the data owner if write operations are included in the scheme.To solve this matter, a protocol was proposed for collaborative processing of outsourced data that allows the authorized users to carry out write operation without being able to change the access policy stated by the data owner.The scheme went along with a light weight signature scheme.The implementation and comprehensive performance analysis of the scheme indicated that the proposed scheme was satisfactory for real mobile applications.Moreover, the security analysis indicates that the security characteristics of the system were not exposed.
Another study was done by Jadoon et al (2018) [5].A study about developments in vehicular networks from the point of view of lightweight cryptographic protocols and privacy maintaining algorithms were presented.They argued that lightweight cryptographic protocols play an important part in order to address the upcoming security issues in future automotive technology, especially regarding vehicular safety and Traffic efficiency.Security concerns for the future automotive industry is acting as an obstacle in the broad distribution of vehicular networks commercially.There is a need for comprehending security risks and coming up with a resolution to secure automotive technology by either developing new lightweight cryptographic protocols or using existing algorithms in an efficient way.The public adoption for new technology in vehicular networks can only be guaranteed by improving the security and privacy of users.Also Usman et al (2017) [6] proposed a lightweight encryption algorithm which was named Secure IoT (SIT).It was based on a 64-bit block cipher and requires 64-bit key to encrypt the data.The architecture of the algorithm was a combination of feistel and a uniform substitution-permutation network.Their result showed the algorithm provides substantial security in just five encryption rounds.Another study was done by Avik et al (2018) [7].
Here, a lightweight sponge mode for AE focusing on the state size as well as optimizing the security was presented.It was instantiated with two versions, where the first version Beetle [Light+] aimed to be lightweight and the second version Beetle [Secure+] aims to be highly secure.Also, the hardware implementation results were presented, which demonstrated the effectiveness of their approach.
Another study was performed by Nilupulee A. Gunathilake et al (2019) [8], they discussed the execution, issues and futuristic applications of LWC algorithms for smart IoT devices, especially the efficiency of Long-Range Wide Area Network (LoRaWAN) which is an open standard that decribes the communication protocol for Low-Power Wide Area Network (LPWAN) technology.The final evaluation showed promising possibilities in the direction of successful implementation of LWC and its performance towards 5GN smart cities.
In this paper, an enhanced modified HISEC algorithm is proposed.The proposed algorithm showed a quality performences after passing some testing stages.

2.The Highest Security Lightweight Block Cipher Algorithm (Hisec)
In this algorithm the following features were used: splitting the plain text into two parts, using the S-box for the whole text, switching bits, is (rotation and XOR), as well as the process of exchanging between two parts and an action Key update.HISEC uses non-fixed size plain text and is processed on a 64-bit block and 80-bit key size.There are 16 rounds and, in each round, there are operations such as: Substitution with S-box, Bit Permutation, XOR, Rotate operation as well as key update, and moreover there is XOR between the encoder text and the key in the last session.HISEC has four layers as shown in figure 1.

In dex
Master key 80 bit val ue S-box Key dependent in improved HISCE algorithm is discribed in Figure 5.The size of the main key is 80 bits and the primary key was taken from the left side.From the position of the primary key, 3 bits will be obtained to represent the number of the S-box.
It is worth noting in the improved HISEC algorithm that the probability of selecting the S-box is (2) 3 and since there are eight S-boxes, the probability of selecting eight S-boxes in one round is (2) 24 as the improved HISEC algorithm consists of 16 a cycle.The total probability of all rounds of selecting a S-box is (2) 384 , which is a large number that is difficult to be known and guessed when S-box is chosen.

4.Security Discussion
Cryptanalysis is a major element in examining the security of the algorithm as it is used to evaluate the security of any algorithm and this is done by using the cryptanalysis test.One of the famous attack is the differential attack where it is the most effective method to determine the resistance of any encryption algorithm against the differential cryptanalysis is to count the minimum active S-box.The number of active S-box for the proposed HISEC algorithm after 16 rounds is 124 while this attack can not count the minimum active s-box for the proposed algorithm because the s-boxes are unknown.

5.Cost Discussion
The cost of the algorithm is an important factor in the design of any algorithm [12,13].Here, it shows thecalculated cost of the proposed HISEC algorithm according to each operation in the algorithm based on what will be done and what it requires from GE.As the process of storing one bit of data requires (6 GE), the use of one S-box requires (22) GE), OR requires (1.33GE), MUX (Multiplexing) requires (2.67GE).[2].
The cost will be calculated as follows: • 64-bit size plaintext: the cost is 64 x 6 = 384 GE.
• 80 bits the size of the master key: the cost is 80 x 6 = 480 GE.
• 16 S-boxes for both the left and right sides: the cost is 16 x 22 = 352 GE.
• a key update process in every cycle: we use one of the S-box x 22 + the used S-box selection (MUX) 4 bits x multiplied by 2.67 + plus 8 bits x 2.76 = 22 + 22.08 + 10.68, so the total is 54.76 GE.
The cost of HISEC is 1694GE which is roughly equal to the cost of proposed HISEC algorithm.

6.Experiments And Results
In the cryptography field, the Avalanche test refers to the random characteristic of cryptographic algorithms in general [8].It is an examination through which it is possible to know the extent of the randomness of the algorithm used for encoding.In this experiment, a 64-bit Plaintext (Abdallah) with an 80-bit Key (ComputerSc) in the first case was used.Then using the same plaintext with one bit change in the key (CnmputerSc) also is encoded.It is found that the value of Avalanche test is nearly half as in Table (1).In block cipher algorithms, when a small change occurs in the original text or key, it leads to a very large change in the ciphertext.If the encoded text achieves the Avalanche test with a value much more than half or with a value much less than half, this indicates weakness of randomness.Avalanche test is calculated according to Equation 1 [12][13][14][15].

Figure ( 5 )
Figure (5) Process of key dependent S-box in proposed HISEC Algorithm